Guilty as Charged?

Brain activity tests to tease out guilty memories aren’t as foolproof as some people think. So says new research from a team of European scientists.

The tests’ premise is that brain activity scans can show when guilty people recognize details from a crime. When researchers told test subjects to suppress memories of a mock crime, however, some people successfully beat the tests.

While the tests aren’t used in American courts, law enforcement agencies in some other countries do use them, including India and Japan. “Using these types of tests to say that someone is innocent of a crime is not valid because it could just be the case that the suspect has managed to hide their crime memories,” says lead investigator Zara Bergstrom in the press release announcing the study results. Bergstrom is a cognitive psychologist at the University of Kent.

“Interestingly, not everyone was able to suppress their memories of the crime well enough to beat the system,” notes co-author Michael Anderson at the Medical Research Council in Cambridge.

In other words, the tests may have some use, in the same way that lie detector tests have some use. But they’re not conclusive. Nor should their results be admissible in court.

On one level, the whole business of tracking memories with brain activity sounds like something out of Star Trek Voyager or Deep Space Nine. Are we just a few steps away from Total Recall?

At another level, the research reaffirms something we all know. Some people are really good liars. Of course, this isn’t good when someone has committed an heinous crime.

But maybe we don’t want high-tech tests to be able to tease out all our memories. Maybe sometimes we just want to keep a secret to ourselves.